# Thermodynamics (11-20)

11.

If all the variables of a steam are in-dependent of time it is said to be in

 A. Steady flow B. Unsteady flow C. Uniform flow D. Closed flow E. Constant flow

Explanation:

12.

A control volume refers to

 A. A fixed region in space B. A specified mass C. An isolated system D. A reversible process only E. A closed system

Explanation:

13.

Internal energy of a perfect gas depends on

 A. Temperature, specific heats and pressure B. Temperature, specific heats and enthalpy C. Temperature, specific heats and entropy D. Temperature and specific heats E. Temperature only

Explanation:

14.

The vapour pressure of water at 30?C in pascals is

 A. 0.44 B. 7.18 C. 223 D. 431.5 E. 4315

Explanation:

15.

According to Charle’s law

 A. At constant pressure the volume of a gas is proportional to its temperature B. At constant pressure the volume of a gas is proportional to its absolute temperature C. At constant gauge pressure the molecular folume of a gas is proportional to its absolute temperature D. At constant volume the absolute pressure is proportional to absolute temperature E. None of the above

Explanation:

16.

The perfect heat engine works on the Carnot cycle between 1000?C and 200?C. The efficiency of the engine will be

 A. 80% B. 60% C. 62.80% D. 37.20% E. 68.20%

Explanation:

17.

In a reversible polytropic process

 A. Some heat transfer occurs B. The entropy remains constant C. The ethalpy remains constant D. The internal energy remains constant E. The temperature remains constant

Explanation:

18.

The velocity potential exists

 A. For all types of continuous flow B. Only for rotational flow C. Only for irrotational flow D. Only for laminar flow E. Only for unidirectional flow

Explanation:

19.

An isentropic process is always

 A. Irreversible and adiabatic B. Reversible and isothermal C. Frictionless and irreversible D. Reversible and adiabatic E. None of the above

Explanation:

20.

An ordinary mercury thermometer can be used for temperatures about

 A. 100?C B. 200?C C. 300?C D. 400?C E. 500?C